Various processes have been suggested for the stabilization of bromostyrenes. Amongst these there may be mentioned U.S. Pat. Nos. 4,376,221, 4,276,189, 4,342,956, 4,338,474.
It is one of the drawbacks of the known processes that extremely high amounts of stabilizer (TBC, propyl gallate hindered amines etc.,) of the order of 800 ppm--are required to effect an acceptable degree of stabilization. Since the accepted practice in Industry is to effect polymerization without removing the inhibitor, amounts of 800 ppm introduce a level of impurities in the polymer that adversely affect the quality of the final products (colour, light stability, etc). The existing practice in the art calls for avoiding the use of stabilizers in excess of about 150 ppm in styrene monomer and the like.